Process of electrodepositing indium and indium and silver



Patented Nov. 21, 1933 PROCESS OF ELECTRODEPOSITING IND AND INDIUM ANDSILVER Daniel Gray, Oneida, N. Y., assignor to Oneida Community,Limited, Oneida, N. Y., a corporation of New York No Drawing.Application May 11, 1927, Sam No. 190,653. Renewed August 9, .1932

Claims.

This invention relates to a process of electrodepositing indium, andmore particularly indium and silver, for the production, in either case,of tarnish-resisting products, either in the 5 form of finishedarticles, except for polishing, etc., or in the form of raw materialswhich may be used for various purposes including that of fabricationinto finished articles.

I have observed in the use of alkaline baths from or through whichindium, alone or together with silver, is to be plated, that after atime a compound containing the indium is precipitated fromthe bath,rendering the bath valueless for the purpose of electro-depositingindium.

I have discovered, as the result of various experiments, that this maybe efiectively prevented by the introduction into the bath of an organiccompound of an acid nature which will effect the retention of the indiumin solution and thus cause it to be properly plated.

Various organic compounds of an acid nature may be used, such asglycine, cyanuric acid, abietic acid, adipic acid, acetyl m-aminobenzoicacid, acetyl p-aminobenzoic acid, acetaldehyde sodium bisulphite,m-aminobenzoic acid, so long as the compound used is one which, likeglycine for example, will remedy the difl'iculty referred to without, atthe same time, injuriously affecting the bath.

Such agent or agents may be used where indium alone is plated, or whereindium and silver are simultaneously plated, and where the indium orindium and silver are plated from the bath, in which case an insolubleanode is used, or through the bath from anodes of indium or indium andsilver. Where the two metals are simultaneously plated through the bathI prefer to use an anode consisting of an alloy or intimate mixture ofthe two metals instead of an anode of each.

In the following description the process will be described specificallyin connection with the plating of indium through the bath and theplating of indium and silver through the bath by the use of such analloy anode of indium and silver.

PROCESS 1 Indium plating Potassium cyanide 15 ozs. avoir. Glycine '7ozs. avoir.

Water 1 gallon Current density about .035 amperes and upwards per squareinch at the cathode. The cathode and an anode of indium being immersedin the bath, current will be passed through the bath from the anode inorder to efiect a partial solution of the anode and thereby introduceindium into the bath in sufiicient quantity to give a suitable depositon further electrolysis.

Pnoorzss 2 IndiumSilver plating A bath such as that just described isprepared 5 and an anode alloy or intimate mixture of indium and silveris immersed in the bath. Current is then passed through the bath fromthe anode to eifect a partial solution of the anode and therebyintroduce both indium and silver in sumcient 7 quantities to give asuitable deposit of both metals on further electrolysis.

This process may also be used with two anodes, one of indium and theother of silver.

It may also be used for plating indium or indium and silver from thebath, which for that purpose will be made up with the indium or indiumand silver as ingredients thereof. In that case an insoluble anode willbe used, for example, one of carbon or platinum.

What is claimed is:

1. A process of electro-depositing indium which comprises the steps ofimmersing an article to be plated as the cathode in a prepared bath,said bath comprising 1 gallon of water, 15 oz. potassium cyanide, and 7oz. glycine, or equivalent thereof selected from the group: cyanuricacid, abietic acid, adipic acid, acetyl m-aminobenzoic acid, acetylp-aminobenzoic acid, acetaldehyde sodium bisulphite, m-aminobenzoicacid, immersing an anode of indium in said bath, and passing a currentof about .035 amperes and upwards per square inch at the cathode todeposit indium on said article.

2. A process of electro-depositing indium which comprises the steps ofimmersing an article to be plated as the cathode in a prepared cyanidebath containing a material selected from the group: glycine, cyanuricacid, abietic acid, adipic acid, acetyl m-aminobenzoic acid, acetylp-aminobenzoic acid, acetaldehyde sodium bisulphite, m-aminobenzoicacid, immersing an anode of indium in said bath, and passing a currenttherethrough to deposit indium on said article.

3. A process of electro-depositing indium-silver alloy which comprisesthe steps of immersing an article to be plated as the cathode in aprepared cyanide bath containing a material selected from the group:glycine, cyanuric acid, abietic acid, adipic acid, acetyl m-aminobenzoic5. In the process of electro-depositing indium and silversimultaneously, the steps which comprise immersing an article to beplated as the cathode in a prepared cyanide bath containing glycine,immersing an anode of indium and silver in said bath, and passing acurrent therethrough to deposit indium and silver on said article.

DANIEL GRAY.

